The removal of undesirable components from products which are consumed, while retaining the pleasant characteristics of the products, is of considerable interest. Beverages produced by an aqueous extraction process, such as coffee and tea, often contain undesirable flavors. This may be caused by using tea leaves or coffee beans of an inferior quality, or by allowing the extracting water to remain in prolonged contact with the leaves or beans. However, even properly prepared tea or coffee contains dissolved compounds which impart a bitter or astringent taste to the beverage. Since some of these compounds, such as caffeine, have raised concern over potential detrimental health effects, the reduction or removal of these materials from ingested beverages is desirable.
Tea should have a relatively low to mild astringency. Tannins, polyphenolic compounds of molecular weight 500 to 3000, present in tea, are known to interact with salivary proteins in the mouth to form tannin-protein complexes. These complexes can precipitate, resulting in a puckering mouthfeel referred to as astringency. However, once the tannins form soluble complexes, they are much less likely to bind salivary protein. Although some astringency in tea is desired, excessive astringency and bitterness can provide an unpleasant mouthfeel. Thus, reducing the astringency and perceived bitterness of tea is desirable.
Tea beverages should also have a fresh brewed flavor. The principal polyphenols of fresh brewed tea are the theaflavins and the thearubigins. Theaflavins are believed to contribute to black tea flavor and color. Thearubigins are high molecular weight compounds which also contribute to flavor and color. Although theaflavins make significant contributions to the flavor and appearance of a tea beverage, they are almost always present in lower amounts than the thearubigins. However, too high a ratio of thearubigins to theaflavins is indicative of a tea beverage having a flat taste and a dull appearance. Preferred teas have a thearubigin to theaflavin ratio similar to that of fresh brewed tea.
In the case of regular coffee, water is boiled in a coffee pot in advance, and ground roasted coffee beans are directly placed in boiling water (a standard amount is 2.2 g of ground roasted coffee beans per 100 ml of boiling water) and are boiled to effect extraction or are similarly extracted by using a percolator or the like. The resulting extract contains caffeine, tannic acid, saccharides, fats, proteins and various aromatic components and has a good fragrance inherent to coffee and a peculiar complicated flavor inclusive of a bitter taste, an astringent taste and an acid taste. When roasted coffee beans are ground and then allowed to stand in air, they are readily oxidized which degrades the fragrance. When tepid water is used for extraction, the contact time for extraction of roasted coffee beans is increased, thus further degrading the fragrance and flavor. It is thus very difficult to consistently obtain coffee rich in flavor and fragrance.
Reducing or eliminating objectionable flavor components from aqueous extracted beverages has been attempted with cyclodextrins--cyclic oligosaccharides which complex the bitter or otherwise undesirable compounds and mask their taste (U. S. Pat. No. 3,528,819 to Hamilton et al.). Cyclodextrins have also been utilized to produce a dried instant-coffee beverage (U.S. Pat. No. 4,560,571 to Sato et al.) without the accompanying bitter, astringent or acidic flavors. However, using cyclodextrins for this purpose results in ingestion of compounds which have been complexed, posing potential detrimental health effects. In addition, the cyclodextrins are also ingested and may themselves be a health risk. Finally, the cyclodextrins also impart a slightly sweet flavor of their own to the beverage to which they are added.
Utilizing a filtration or chromatography process to selectively remove the compounds which cause cloudiness in iced tea beverages without impairing the full-bodied tea flavor, has also been described (U.S. Pat. No. 4,004,038). However, this is a lengthy process requiring gel filtration, displacement washing to obtain the desirable components and a pH adjustment. This process may also involve the use of organic solvents such as acetone which must then be carefully eliminated to avoid contamination of the resulting product.
The sequestration of undesirable components, such as those found in the smoke from lighted tobacco products, from a vapor phase is also desirable in view of the many health risks known to be associated with second hand smoke. Nicotine, in addition to possessing an acrid, burning taste, is highly toxic (Merck Index, 11th edition, 1989, Merck and Co., Rahway, N.J., No. 6434), addictive, and has been associated with many of the harmful effects of smoking tobacco products. Cellulose acetate filters are commonly employed for the purpose of reducing the amount of nicotine present in smoke, but a substantial amount of nicotine passes through the conventional filter and is inhaled. In addition, the cellulose acetate fibers may contain residual amounts of the chemicals used in their production and, being a semi-synthetic polymer, do not readily degrade in the environment when discarded.
The present invention overcomes the prior art disadvantages by using a proteinaceous particulate material derived from seeds to sequester and remove undesirable components from beverages and tobacco smoke.